Archives Séminaires 2018-2019

Séminaire

Séminaire IPAG de Maria Drozdovskaya (CSH Bern), jeudi 11 octobre 2018 à 11h00, salle Manuel Forestini

Comet 67P/Churyumov-Gerasimenko has been studied with in situ measurements by various instruments (ROSINA, COSAC, VIRTIS, MIRO, ALICE, etc.) aboard the Rosetta spacecraft, which show that the comet has a rich molecular inventory and that there are complex relationships between various species. These data are one of the best probes of the innate protosolar disk that evolved into our modern day Solar System. Similar chemical richness, including large complex organic species, extends beyond (...)

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Séminaire IPAG de Jérôme Bouvier (IPAG), jeudi 4 octobre 2018 à 11h00, salle Manuel Forestini

I will review recent results regarding the evolution of key properties of young solar-type stars over the time frame 1-10 Myr, i.e., at the time when planets form in the disk. The presentation will include an overview of recent magnetic field measurements in young stars and how stellar magnetism evolves with time. I shall discuss the implication of the strong magnetic fields of young stars on the star-disk interaction process, and most notably illustrate the evidence for magnetospheric (...)

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Séminaire IPAG de Daniel Hestroffer (IMCCE), jeudi 27 septembre 2018 à 11h00, salle Manuel Forestini

The Gaia ESA space mission provided its first harvest in 2016, with the DR1 catalogue release ; yielding improved astrometry from classical ground-based observations of Solar System Objects (SSOs). Albeit of high interest, the DR1 data release has been largely surpassed by the DR2 release. Indeed, the Gaia DR2 is a major step in the Gaia mission by providing the very first full stellar catalogue, that includes all astrometric parameters (positions, parallaxes, and proper motions) at (...)

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Séminaire IPAG de Reinhard Genzel (MPE Garching & UC Berkeley), jeudi 20 septembre 2018 à 11h00, salle Manuel Forestini

The Center of our Galaxy is a unique laboratory for exploring the astrophysics around a massive black hole and testing General Relativity and other theoretical concepts in this extreme environment. I will discuss the results of a major campaign of observing the Galactic Center in 2017/2108 with three instruments at the European Southern Observatory’s VLT, including the novel GRAVITY interferometric beam combiner of the 4 UTs. During this period the B-star S2 completed a peri-passage at 1400 (...)

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Séminaire IPAG de Amelia Bayo (Universidad de Valparaiso), jeudi 13 septembre 2018 à 11h00, salle Manuel Forestini

Debris disks can be seen as the left-overs of giant planet formation and the possible nurseries of rocky planets. While M-type stars out-number more massive stars we know very little about the time evolution of their circumstellar disks at ages older than ∼ 10 Myr. Sub-millimeter observations are best to provide first order estimates of the available mass reservoir and thus better constrain the evolution of such disks. Here, we present ALMA Cycle 3 Band 7 observations of the debris disk (...)

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Séminaire IPAG de Ivana Orlitova (IPAG & Astronomical Institute of the Czech Academy of Sciences), jeudi 6 septembre 2018 à 11h00, salle Manuel Forestini

Reionization of the universe in the first billion years of its history represented a major change. However, the sources that caused it are still being debated. Quasars may have been too rare in that epoch, while star-forming galaxies face the problem of inefficient ionizing radiation escape : the fraction that can escape into the intergalactic medium depends on the structure of the interstellar medium. I will present a rare class of nearby star-forming galaxies, known as green peas, which (...)